loving your work so far ,looking at the reference photo earlier the gate symbols seem more a part of the gate,those seem a little stuck on , im sure ive seen a boolean plugin that solves this by welding the two objects together, i know you are trying to keep it boolean free ;-) i just dont know to what level of realism you are going for on this. also the leaf shaped decorations near the outer part of ring seem to be very flat edged, where the photo they seem to be fairly rounded, however this might look better when textured or with a bit of AO applied? cant wait to see next stage man